You don't say precisely what you're doing (what field you use for thematic formatting, or the method, etc. used), so I'll guess.
The issue came about when trying to apply a style based on the city's name. Not all of the cities in the database show up when applying a style.
I suppose you are doing a thematic format using the CITY_NM field. Looks like over half of the records have no name (NULL value), so that's possibly an issue. Also, if you are using the CITY_NM field that is a text field and your only choice for a method is unique values, which allows you up to 100 breaks.
Why only 100 breaks for unique values? The purpose of thematic formatting is to provide a visual way of understanding differences. Humans get confused long before 100 different shades of color are used, and cannot tell which of various points or areas in nearly identical shades, scattered about in a map, are different.
Use a different method of grouping and coloring if different shades are desired for many different objects. For example, add a pseudorandom field (see the Computed Fields topic) and color on that, as done below: